Spatial structure of a light beam is an important degree of freedom to be extensively explored. By designing simple configurations with phase-only spatial light modulators (SLMs), we show the ability to arbitrarily manipulate the spatial full field information (i.e. amplitude and phase) of a light beam. Using this approach to facilitating arbitrary and independent control of spatial amplitude a...

Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency ∼40–400 kHz which they radiate. The electron beams occur ∼2–9 ms after positive cloud-to-ground lightning discharges at heights between ∼22–72 km above thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron b...

In order to achieve the highest intensities possible with the short-pulse Advanced Radiographic Capability beamline at the National Ignition Facility (NIF), it will be necessary to phase the individual ARC apertures. This is made especially challenging because the design of ARC results in two laser beams with different dispersions sharing the same NIF aperture. The extent to which two beams wit...

Intense low energy muon beams – as part of a muon collider complex – may become available for use in radiotherapy. It is of interest to compare their effectiveness in this application with that of hadron beams in a setting where processes common to these beams are treated exactly alike. Detailed simulations of physics processes for muon, proton, antiproton, neutron, kaon and pion beams stopping...

With the increase in applications of heavy ions in various fields, the production of intense beams of highly charged heavy ions from ion sources become more and more important. For example, the ion sources are required to produce intense dc beams of highly charged heavy ions for accelerator facilities for radioisotope beam production, and intense short-pulsed beams for injection into synchrotro...

Bessel-Gauss beams are known as non-diffracting beams. They can be obtained by focusing an annularly shaped collimated laser beam. Here, we report for the first time on the direct measurement of the phase evolution of such beams by relying on longitudinal-differential interferometry. We found that the characteristics of Bessel-Gauss beams cause a continuously increasing phase anomaly in the spa...

Light propagation in a cholesteric medium has been completely discussed by de Vries [2]. The main results are that, for a given frequency, there are two eigenvibrations with quasi-circular polarizations, except i) for high frequencies and ii) near the reflection band (for the vibration having total reflection), where the polarization is linear. Looking at light refracted by a cholesteric prism,...

This paper reports novel characteristic features of thermally-passivated Si nanoelectromechanical (NEM) beams fabricated via SOI-CMOS compatible processes with top-down hybrid EB/DUV lithography. Considerable difference of the resonance frequencies between the measurement results of the NEM beams with various lengths and the finite element simulation results suggests that effects of the undercu...

We demonstrate a terahertz (THz) beam steering method using difference frequency generation that is based on the principle of phased array antennas. A strip-line photoconductive antenna was illuminated by two spatially dispersed beams produced from an ultrafast laser. THz radiation with a bandwidth of 65 GHz was generated from the overlapping area of the two beams, between which the frequency d...

Characteristics of electron-cooled bunched ion beams have been studied using the particle-tracking simulation in which the space-charge force and the force induced through the transverse broadband impedance are taken into account. The beams become space-charge dominated during the bunching of coasting beams. The simulation results show that the beams meet the transverse instability which can be...